Method of and apparatus for adjust



Dec. 22, 1936. F j GROVEN 2,065,067

METHOD OF AND APPARATUS FOR ADJUSTING IGNITION DISTRIBUTORS Filed July 30, 1934 INVENTOR.

Patented Dec. 22, 1936 UNITED" STATES METHOD OF AND APPARATUS FOR ADJUST- ING IGNITION DISTRIBUTORS Fredrick J. Groven, Highland Park, Mich., as-

signor to Ford Motor Company, Dearborn,

Mich, a corporation Application July 30,

6 Claims.

The object of my invention is to provide an improved method of adjusting the gap between the contact points of distributors associated with internal combustion engines, which method may be performed by relatively unskilled labor to produce an adjustment within a degree of accuracy heretofore not obtained even bythe most skillful mechanic.

This method and apparatus is particularly adapted for use in connection with those internal combustion engine distributors which require an exceedingly accurate contact point gap adjustment. While some distributors do not require an adjustment within close limits, still other dis tributors require an exceptionally close adjustment for successful operation and it is in connection with these latter types of distributors that my method and apparatus finds its greatest utility. A distributor of this latter mentioned type is shown and described in United States Patent 1,963,657, which patent relates to a method of timing a distributor so that-the high tension spark. is synchronized with the piston to fire the cylinder at the correct instant for each condition of the engine. However, the successful operation of the method described in the above mentioned patent is predicated upon the contact points having previously been set to a given dimension within close limits. The method and apparatus described in this present specification relates solely to the-means for accurately adjusting the gap between thecontact point so that the method of timing described in the patent mentioned may be more accurately accomplished. I

With these and other'objects in view, my invention consists in the arrangement and construction of my improved apparatus together with the method of operating same, as described in the specification; claimed in my claims, and

--illustrated in the accompanying drawing, in

which:

Figure 1 is a perspective view of my improved device.

Figure 2 is-a sectional view, taken through the breaker plate of the distributor to be adjusted.

Figure3- is a vertical, sectional view taken through the driveshaft of the apparatus shown in Figure 1, and V Figure 4 is an electrical diagram showing the electrical connections between the several parts of theapparatus.

In order to adjust the gap of the distributor contact points it has been in the past a universal custom to provide a feeler gauge which is inserted between the contact points in their exof Delaware 1934, Serial No. 737,501

treme open position, the gauge being of a thickness corresponding to the required gap. The disadvantage of such method is that it is essential that the points be separated to their maximum opened position before the adjustment is made as a slight angular movement of the distributor cam from its exact high point will cause a measurable variation in the spark gap. Such positioning of the cam has always been onlyan approximation and errors invariably occurred. Furthermore, some distributors are constructed so that the insertion of a feeler gauge is difiicult and in many cases inaccurate adjustments have been made, due to the gauge being held in a nonparallel position between the contact points. The purpose of this invention is to eliminate the errors resulting from these disadvantages, especially when applied to distributors requiring a close adjustment of the point gap.

Before describing my improved method of ad- I justment, it may be well to describe briefly the various parts of the distributor which is to be adjusted.

This distributor comprises a housing In in which a breaker plate assembly II is mounted. Distributor arms I2 and I3 coact with contact points I 4 and I5, respectively, the arms and points being mounted upon the plate II so as to extend inwardly into the housing. A single rotor cam I6 actuates both arms I2 and'l3. A pair of annular openings 35 in opposite sides of the housing provides the only access to the space directly above the contact points so that difiiculty is encountered in both setting the cam I6 on its high point and in operating the feeler gauge to secure accurate adjustment of the contact points in the conventional manner. In connection with this distributor, it may also be well to mention that the two sets of contact points are electrically connected in multiple with the primary of the ignition coil and the battery.

In operation, the pair of points I2 and I4 close to complete the electrical circuit and energize the coil while the pair of points I3 and I5 open to break the electrical circuit thereby causing a high voltage spark to be induced in the spark coil. In the distributor shown, eight sparks are produced per revolution of the cam I6 or one every 45 degrees of cam movement. The points I2 and I4 close, then 9 degrees of cam rotation closes points I3 and I5, both sets of points remaining closed until 27 degrees of rotation has occurred at which time points I2 and I 4 open. No spark occurs at this time as points I3 and I5 are still closed and do not open until 36 degrees of movement is completed. In the 9 degree interval between 36 and 45 degrees both pairs of points are open. This type of distributor is particularly adapted for use with 8-cylinder motors inasmuch as only one spark coil is required. However, in order to get the high speeds from the motor it is essential that the points 2 and M close to complete the electrical circuit within 9 degrees of cam movement after points I3 and I5 have opened. It is also essential that the making points do not close before the breaking points open, as in such case no spark would occur, the circuit being unbroken.

From the foregoing, it will be seen that a very close gap adjustment is required as a difference of a few thousandths of an inch in the gap opening will materially change the relative angular positions at which the points open, either causing the openings to overlap thereby destroying entirely the function of the distributor or else causing the completing points to make the circuit too late to allow the storing up of sufiicient energy in the coil for high speed operation. In the commercial adjustment of this type of distributor a variation of less than one-thousandth of an inch in the gap dimensions is desirable which adjustment is very diificult to obtain with the conventional method of adjusting contact points.

In the method of timing about to be described, no feeler gauges of any description are employed, the operation consisting entirely of measuring the electrical conductivity of the circuit at a given speed. A milliammeter is used for this purpose, which meter may be chosen with a total range such that the desired accuracy is easily obtained. A constant voltage current is conducted through each pair of contact points which are in series with the milliammeter, the cam being rotated at 900 R. P. M. It will be apparent that the larger the gap between the pair of points being measured the less current will flow through the circuit. The applicant has found that when a milliammeter having a total range of approximately 50 milliamperes is employed and a six volt battery is used that an adjustment well within the desired range is readily obtained.

Referring to Figure 4 of the drawing, I have provided a conventional 6-volt storage battery H, the positive terminal of which is connected to one terminal of a milliammeter 8, the other terminal of the ammeter having a flexible wire 36 extending therefrom which is operatively connected to the lead-in terminal of the distributor. The negative terminal of the battery is grounded as are the stationary contact points l4 and I5 of the distributor. A three phase synchronous motor I9 having a speed of 900 R. P. M. is directly connected to the cam |6 of the distributor. In order to secure a constant potential from the battery IT, a battery charger is employed. This and rectifying unit 2|.

With the distributor shown each pair of contact points are adjusted separately and consequently one pair of points must be held open while the adjustment is being made on the other pair. This is conveniently done by inserting a strip of fibre between the pair of points not being adjusted.

One form of device for carrying out my improved method is shown in Figure 1 of the drawing wherein a frame 22 is provided upon the lower portion of which the motor I9 is secured with its shaft in a vertical position, A shelf 23 extends horizontally from the frame to position over the upper end of the motor shaft, this shelf having a tubular extension 24 fixed thereto which extends down over the upper end of the motor shaft. A driving shaft 25 is rotatably mounted in the member 24 in a suitable bearing 26, the driving shaft being directly connected to the motor shaftby means of a coupling 21. The upper end of the shaft 25 is provided with a slot .28 therein which is adapted to coact with a tongue formed on the rotor shaft of the distributor to thereby directly connect the motor to the distributor rotor.

The frame 22 extends upwardly from the shelf 23 and the milliammeter I8 is secured on the upper portion of the frame. A bracket 28 extends laterally and rearwardly from the lower portion of the frame 22, the upper end of the bracket having an arm 29 pivotally mounted upon its rearmost edge, the free end of the arm being arranged to swing into engagement upon the top of the distributor housing II] when the latter is placed in position upon the shelf 23. A plunger 30 is reciprocally mounted in the free end of the arm 29 and a compression spring is interposed between the arm and the head of the plunger to thereby resiliently urge the plunger against the distributor housing |ll when the arm 29 is moved to its engaging position. An operating lever 3| is pivotally secured to the intermediate portion of the arm 29 and a toggle link 32 has its ends secured respectively to the intermediate portion of the handle 3| and to the forward portion of the bracket 28. The device is so constructed that when the lever 3| is moved rearwardly to the position shown by dotted lines 33, the arm 29 will be raised to its inoperative position. When the lever 3| is moved forwardly then the toggle link 32 draws the arm 29 downwardly so that the plunger 30 coacts with the upper portion of the distributor to resiliently secure it in position upon the shelf 23. I

In carrying out my improved methods the motor 9 is switched on and then a distributor is then brought down in position on the shelf 23. The handle 3| is then pulled forwardly which holds the distributor in fixed position. A fibre strip is inserted between either pair of contact points, say l2 and I4, and then the free end of the flexible connection 36 is snapped on to the low voltage input terminal of the distributor. The circuit is now completed and a reading will occur on the milliammeter. The operator then adjusts the contact screw l5 until the needle of the milliammeter coincides with a line 34 on the meter. The insulation strip is then removed and inserted between the points l3 and I5 and then the screw I4 is likewise adjusted until the meter needle coincides with the line 34. The lever 3| is then pushed back and the distributor removed from the shelf 23 so that the aforementioned operation may be performed upon another distributor.

It may be well to mention that by this method practically no skill is required in obtaining a very accurate measurement of the contact point gap and of course no calculations or similar technical operations are required. The milliammeter should be calibrated for its particular distributor to be adjusted, the position of the line 34 being ascertained from a correctly adjusted distributor. However, it is quite conceivable that the meter may readily be calibrated to read in units of length of the distributor gap so that any desired contact point gap opening may be readily pro-.75

cured. Inasmuch as this device is primarily a production machine for adjusting the contact points of distributors before they leave the factory, it is believed preferable to provide a single line scale, as shown, so that error in reading the meter will be practically eliminated.

Among the many advantages arising from the use of my improved method and device, it may be well to mention that an extremely accurate adjustment is conveniently obtained without the use of feeler gauges or similar mechanical apparatus. Furthermore, the adjustment is so easily accomplished by this method that even an unskilled operator may accurately adjust the distributor in less than one-fourth the time heretofore required for skilled operators to adjust similar distributors by the conventional method.

Some changes may be made in the apparatus for carrying out my improved method, as well as in the steps which comprise my method, without departing from the spirit of my invention, and it is my intention to cover by my claims, such changes as may reasonably be included within the scope thereof.

I claim as my invention:

1. The method of ascertaining the length of the spark gap between ignition distributor contact points comprising, conducting current through said points while rapidly making and breaking said current by means of said points, and measuring the amperage of the current passing through said points, said current being substantially inversely proportional to said gap.

2. A device for adjusting the spark gap between ignition distributor contact points comprising, means for rapidly rotating the distributor cam, a current source, a milliammeter, and means for electrically connecting said source and contact points and milliammeter, so that said milliammeter will read the average amount of current flowing through said points.

3. A device for adjusting the spark gap between ignition distributor contact points comprising, a frame, a shelf secured to the frame, a motor mounted upon said frame with its shaft extending towards said shelf, a driving shaft rotatably mounted upon said shelf, said shaft being fixed to the motor shaft for rotation therewith, a milliammeter secured to said frame, a driving connection formed on the free end of said driving shaft, and means for clamping a distributor down upon said shelf so that the distributor shaft is rotated by said driving connection, said milliammeter and distributor contact points being connected in series with a current source.

4. In an apparatus for testing the breaker mechanism of the ignition system of an internal combustion engine to determine the length of time the points of the breaker mechanism are closed to energize the spark coil, the combination of an ammeter, a source of direct current in series circuit relationship to form a non-inductive circuit, means for connecting the breaker mechanism to be tested in series circuit relationship therewith, and means for driving said breaker mechanism.

5. The method of testing the breaker mechanism of the ignition system of an internal combustion engine todetermine the relative length of time the breaker points are closed to energize the spark coil, comprising passing a current of electricity through the breaker mechanism, said current of electricity being of such character that on closing the points it attains its full strength substantially instantaneously and that on opening of the points said current ceases flowing substantially instantaneously, operating said breaker mechanism at an operating speed thereof, and measuring the average current passing through the breaker mechanism during operation thereof.

6. The method of testing the breaker mechanism of the ignition system of an internal combustion engine to determine the relative length of time the breaker points are closed to energize the spark coil, comprising passing a current of electricity through the breaker mechanism, operating said breaker mechanism at an operating speed thereof, and measuring the average current passing through the breaker mechanism during operation thereof.

FREDRICK J. GROVEN. 

